1. Field of the Invention
The present invention relates to an organic photosensitive member excellent in durability having a vacuum thin layer as a surface protective layer.
2. Description of the Prior Art
Recently photosensitive members for electrophotography which are made by dispersing an organic photoconductive material to a binding resin have been widely utilized.
This type of photosensitive members are free of hygienic problems and profitable in industrial productivity by virtue of their excellent processing characteristics in comparison with photosensitive members formed of selenium or cadmium sulfide.
However, these organic photosensitive members are generally so poor in hardness that they are liable to be shaved or injured by the friction with transfer paper, cleaning materials, developer and others when used repeatedly.
A technology has been known to form a surface protective layer over the organic photosensitive layer for solving this problem.
As one of such surface protective layers, a vacuum thin layer made of an appropriate compound has been proposed.
It is possible to make a vacuum thin layer with a high hardness, and an organic photosensitive member having such a vacuum thin layer over the organic photosensitive layer as the surface protective layer will show higher durability in comparison with an organic photosensitive member without a surface protective layer, and will keep sufficient layer hardness in usage for a long period under ordinary temperature and humidity. However, in repeated usage electric charge tends to be accumulated on the interface between the surface protective layer and photosensitive layer with the result of rise of residual potential, lowering of sensitivity, and occurrence of black thread-like image noise.